Miner&#39;s drill bit and other tools



Nov. 26,

M. J. GALVIN I MINERS DRILL BIT AND OTHER TOOL Original Filed Oct. 28, 1953 INVENTOR.

' Patented Nov. 26, 1935 PATENT OFFICE man's mum. nrr AND o'rnas 'roons- Mlcha'el Joseph Galvin, Toronto, Ontario, Canada lpplioatlon October 2a, 1933, Serial No. assess. mlaewed October 15, 1935. In Canada July 13,

-2 Claims. (01. 255-04) My invention relates to improvements in miners. drill bits and other tools, and the object of the invention is to devise a bit or tool of this type the life of which is materially increased by providing a plurality of cutting edges which may be readily interchanged as each edge becomes worn, by providing separable cutting portions of very high grade material thus permitting the use of low grade material for the body of the bit or tool thereby decreasing the cost of manufacture of the bit or tool as a whole, by which a tool having high grade cutting portions having' interchangeable cutting edges are available and renewable in remote places without cost and without the excessive transportation costs hitherto necessary when the whole bit had to be discarded and replaced when worn out, and hy which uniformity in the high quality of the material forming the cutting edge is ensured and the,

necessity for sharpening at the mine eliminated, and it consists essentially of the arrangement and construction of parts as hereinafter more particularly explained. t

Fig. 1 is a plan view of my drill bit. I Fig. 2 is a longitudinal section through Fig. 1. Fig. 3 is a transverse section through' Fig. 1. Fig. 4 is a transverse sectional view showing a slight modification.

Fig. 5 is a fragmentary portion oi my drill bit 3 insert showing a cutting edge formed serrated,

. the serrations being chisel shaped.

Fig. 6 is a transverse sectional view through Fig. 5.

Fig. 7 is a perspective view of a rose hit showing my construction applied thereto.

Fig. 8 is a sectional view through Fig. 7.

Fig. 9 illustrates a modified form in which iour inserts are employed.

Fig. 10 is a side elevation of a core drill showing my construction applied thereto.

Fig. 11 is a plan view of Fig. 10.

In the drawing like characters of reference indicate corresponding parts in each figure.

Referring to Figs. 1 to 4.

i is a prism like insert formed of a very high grade of material equilaterally triangular in cross section to form three cutting edges i, P and i.

2 is the bit base which may be formed integral with the steel shank 2* which commonly carrice the bit and which is provided with the usual centre orifice 2 forming the water duct. This portion of the drill may be formed of compara tively cheap low grade material.

. The end of the base 2 is provided with a transverse groove 3, the base of the insert i fitting against the base oi thegroove, the sides 3* of. the groove being undercut so that the inclination of their inner faces conform to the inclination of the sides of the equilaterally triangular insert. The ends of the groove are open so as to permit 5 ghthe insert being slipped longitudinally there- The angles of the groove are recessed as at 3 so as to protect the sharp cuttng edges of the insert so that they will not be dulled by contact 10 with the walls oi the recess.

In order to hold the insert from longitudinal movement I provide a split tube ll which is sprung into the channel 2, the upper end of the tube being split to form tongues 5 and5 which are 15 flattened and bent to tie in the bottom of the channel 2 beneath the insert 8 as shown in Fig.

2, the extreme ends of the tongue being'bent up against the ends of the insert to hold it in place against longitudinal movement as indicated at 5'. 20 In order, to further support the insert i the side walls thereof may be grooved as indicated at 6 and the side walls of the re provided with projections i, see Fig. 4.

If desired the insert may move ireely longiat tudinally to a limited extent in either direction by providing each side wall of the insert with a longitudinal groove 8 of less length than the length of the insert and into which extends projections 9 from the sides of the groove 3 which are of less length than-the grooves of the insert and slidably fitting therein. After the insert is placed in position the es of the groove 8 are 1;. tea-ed into the grooves 8 thereby forming projections 9 extending into the groove and of'so less length than the grooves so as to permit iree longitudinal movement of the insert in the grooves.

Referring to Figs. 5 and 6: In these figures I show an alternative form of insert in which the is cutting edges are formed by a series of chisel shaped projections i0 and i 8 arranged alternately on each side of the cutting centre with their vertical faces directed inward. By this a serrated edge is formed having a greater cut- 45 ting power than the straight edge.

Referring to Figs. 7 and 8, I show my construction applied to a rose bit. In this form the inserts are set radially at the end of the bit as is commonly done in this form and are pressed to outward by means of a split tube having the end split to form spring tongues 02 pressing against the inner end of each insert.

Referring to Fig. 9: In this figure I show a modification in which twelve cutting edges are as in the form of a cross providing a horizontal bearing face l8 at each side of the drill centre on which the horizontal arms of the cross bear.

Water channels H are formed in the groove to convey water from the main channel i8 to the cutting edge in operation.

Referring to Figs. 10 and 11: Inthese figures.

I show my construction adapted to core bits. In this construction is is a tubular body having longitudinal grooves 20 and 2! on its outer and inner faces adapted to receive the triangular inserts 22 and 23 to cut interiorly and exteriorly.

From this description it will be seen that I have devised a tool or bit which provides a plurality of cutting edges which may be used successively as each cutting edge becomes worn, which permits the employment of a very high grade of material for the cutting edges without increasing the cost of the bit as a whole, which does not entail having transportation costs for. renewals which is of particular advantage in remote places where there are no facilities for mak- 5 ing bits for replacement.

Although I have shown the insert i with flat sides it may be formed with convex or concave sides ii! found desirable.

What I claim as my invention is: 10

1. A cutting member for cutting tools comprising a bar equilaterally triangular in cross section and having a serrated cutting edge formed by a series oi! chisel shaped projections set alternately in each side of the cutting line with their ver- 15 tical faces directed inward.

2. In a cutting tool, a cutting member having a plurality of cutting edges, a tool body having an undercut grooved end into which the cutting member is inserted longitudinally to extend be- 20 neath the undercut sides of the groove to have free longitudinal movement, and means extending from the sides oi! the groove and engaging the insert to limit such free movement.

MICHAEL JOSEPH GALVIN. 25. 

